Persistent Toxic Burdens of Halogenated Phenolic Compounds in Humans and Wildlife

Halogenated phenolic compounds (HPCs) including hydroxylated polychlorobiphenyls (OH-PCBs) and hydroxylated polybromodiphenyl-ethers (OH-PBDEs) can be persistent organic pollutant (POP) metabolites or natural marine compounds. Structurally similar to thyroid hormones (THs), they are retained in blood, transported through selective barriers, and the cause of endocrine and neuronal POP effects. This study presents a meta-analysis of HPC burdens in human and wildlife tissues, including OH-PCBs, OH-PBDEs, Pentachlorophenol, and polybromophenols. HPC blood plasma levels were also compared to known <i>in vitro</i> and <i>in vivo</i> toxicological effect concentrations. Blood, highly perfused, and fetal tissues contained the highest levels of HPCs. Plasma concentrations of analyzed OH-PCBs/PBDEs ranged from 0.1 to 100 nM in humans and up to 240, 454, 800, and 7650 nM for birds, fish, cetaceans, and other mammals, respectively. These concentrations fully fall within the <i>in vitro</i> effect concentrations reported in literature for HPCs of 0.05–10000 nM. We strongly advise further study of HPC blood levels in the general population, children, and fetal tissue to establish background levels and the risk at sensitive development stages. As not all HPCs are, or can be, chemically analyzed, the application of additional bioanalysis might reveal an even greater toxicological relevance of HPCs. In addition, metabolic activation should always be included within <i>in vitro</i> hazard assessment of POPs

Protecting the child while preserving the relationship: Using baby’s relational withdrawal to gauge the effect of parental visitation

<div><p>The impact of children’s interactions with parents in the context of out-of-home placements is receiving much-needed cross-disciplinary attention. However, the paucity of instruments that can reliably represent young children’s experiences of such interactions precludes a nuanced evaluation of their impact on wellbeing and development. In response to this empirical gap, the present study investigates children’s relational withdrawal as a clinically salient, easily observable and conceptually valid measure of infants’ and toddlers’ responses to parents. Relational withdrawal, challenging behaviors and salivary cortisol were assessed before, during and after parental visits. Conceptually, the findings suggest that observations of relational withdrawal correlate meaningfully with measure of neurobiological reactivity. Clinically, three profiles of cross-variable responses in children appeared, distinguishing between groups that experience increased, decreased or unchanged levels of stress in response to parental visits. Taken together, the findings lend empirical support to systematic observations of relational withdrawal to bolster evaluations of young children’s experience of parental visitation during out-of-home placements.</p></div

Differently Environment Stable Bio-Silver Nanoparticles: Study on Their Optical Enhancing and Antibacterial Properties

<div><p>Generally, limited research is extended in studying stability and applicational properties of silver nanoparticles (Ag NPs) synthesized by adopting ‘green chemistry’ protocol. In this work, we report on the synthesis of stable Ag NPs using plant-derived materials such as leaf extract of Neem (<i>Azadirachta indica</i>) and biopolymer pectin from apple peel. In addition, the applicational properties of Ag NPs such as surface-enhanced Raman scattering (SERS) and antibacterial efficiencies were also investigated. As-synthesized nanoparticles (NPs) were characterized using various instrumentation techniques. Both the plant materials (leaf extract and biopolymer) favored the synthesis of well-defined NPs capped with biomaterials. The NPs were spherical in shape with an average particle size between 14-27 nm. These bio-NPs exhibited colloidal stability in most of the suspended solutions such as water, electrolyte solutions (NaCl; NaNO₃), biological solution (bovine serum albumin), and in different pH solutions (pH 7; 9) for a reasonable time period of 120 hrs. Both the bio-NPs were observed to be SERS active through displaying intrinsic SERS signals of the Raman probe molecule (Nile blue A). The NPs were effective against the <i>Escherichia coli</i> bacterium when tested in nutrient broth and agar medium. Scanning and high-resolution transmission electron microscopy (SEM and HRTEM) images confirmed cellular membrane damage of nanoparticle treated <i>E. coli</i> cells. These environmental friendly template Ag NPs can be used as an antimicrobial agent and also for SERS based analytical applications.</p> </div

Estimated marginal means of salivary cortisol by group of relational withdrawal.

<p>Estimated marginal means of salivary cortisol by group of relational withdrawal.</p

Estimated marginal means of salivary cortisol as a function of reaction profile (interaction).

<p>Estimated marginal means of salivary cortisol as a function of reaction profile (interaction).</p

Estimated marginal means (logarithmic) for reaction profiles and repeated measures ADBB scores including age and duration of placement as covariates.

<p>Estimated marginal means (logarithmic) for reaction profiles and repeated measures ADBB scores including age and duration of placement as covariates.</p

Colloidal stability of <i>A. indica</i> Ag NPs in different media.

<p>Time dependent UV-Vis absorbance spectra and zeta (HDD and ζ potential value) measurements of <i>A. indica</i> Ag NPs dispersed in different media. <i>A. indica</i> Ag NPs dispersed in (a-b; e-f) NaCl, (c-d; g-h) NaNO₃, (i-j; m-n) BSA, (k; o) pH 7 and (l; p) pH 9.</p

Data collection scheme.

<p>Data collection scheme.</p

Electron microscopy images of bio-Ag NPs exposed <i>E. coli</i> cells.

<p>SEM images of <i>E. coli</i> cells treated with (a-c) <i>A. indica</i> Ag NPs and (d-f) pectin Ag NPs. HRTEM images <i>E. coli</i> cells treated with (g-i) <i>A. indica</i> Ag NPs and (j-l) pectin Ag NPs.</p

Silver nanoparticles characterization.

<p>(a) UV-Vis absorbance spectrum, (b) TEM image (inset SAED pattern) and (c) size distribution histogram pattern of (i) <i>A. indica</i> Ag NPs and (ii) pectin Ag NPs.</p